Yep - it was reading Jan's book "Conundrum" in 1973 or 1974 which first told that sex change surgery was possible. Up until that point I had honestly thought I was going to have to "invent" it!
Ironically Jan went to the same senior school as I did Lancing College. I think we were even in the same house (although not contemporary)! Lightening does strike twice it seems, although she is undoubtedly a far better writer than I will ever be.
When she went there it was an all boys school which must have been pure hell for her!
Happily by the time I arrived in the mid 70's they were already in the process of going co-ed and were admiting a few girls so thankfully I wasn't quite so isolated.